I can't figure out why my coach batteries only last half way through the night. I would assume they should go for days with the little load they get. Here are some details,
* Fridge is on LP
* Heater is set to 60. Only came on once or twice in the night.
* No TV or Lights left on.
* Inverter panel set to off.

When I get up in the morning, the panel reads 8 to 8 to 9 volts and only the smallest lights will work. If I start the Gen the Inverter will not even charge the House batteries since they are so low. I have to start the engine and let it run for 10 to 15 min and the the Inverter will start charging the house batteries. The batteries are stamped Aug 06 so I think they are good. I already checked the levels in them and there fine.

This coach is new to me so I am not sure what to check or do without taking it to a repair shop to troubleshoot. I am very technical so if I can get pointed in the right direction I can fix it myself.

I can't figure out why my coach batteries only last half way through the night. I would assume they should go for days with the little load they get. Here are some details,
* Fridge is on LP
* Heater is set to 60. Only came on once or twice in the night.
* No TV or Lights left on.
* Inverter panel set to off.

When I get up in the morning, the panel reads 8 to 8 to 9 volts and only the smallest lights will work. If I start the Gen the Inverter will not even charge the House batteries since they are so low. I have to start the engine and let it run for 10 to 15 min and the the Inverter will start charging the house batteries. The batteries are stamped Aug 06 so I think they are good. I already checked the levels in them and there fine.

This coach is new to me so I am not sure what to check or do without taking it to a repair shop to troubleshoot. I am very technical so if I can get pointed in the right direction I can fix it myself.

I'll tell you my general electrical opinion but I know nothing about your RV. Hook a current meter up to the battery positive or negative and check if there is current flow meaning something is running. When you locate that, start unplugging things until the current flow goes away and you have your culprit.

Hi Ho: Don's suggestion is good. I just returned a battery stamped Aug. 06. Bad cell. You need to charge the batteries fully and load test them. A hygrometer is cheap and will allow you to check specific gravity, which will point to a bad cell.
Never assume new = good.
Dirk

Today, I just finished checking our motorhome house batteries. Last November (2007), I had checked the fluid levels and Specific Gravity in all cells. When I finished, all cells were reading good. We just got the motorhome back from two weeks in maintenance and the house batteries were totally discharged. When I checked the fluid levels and S.G., every cell need fluid and some acid. I know there have been several recent discussions in this forum about the advantages of switching to AGM batteries which require no maintenance. You might consider looking into getting these batteries.

I've been delighted with the performance of the Lifeline AGMs. I have 4 ea. 6 volt 220 Amp./Hour batteries installed for a total of 440 Amp./Hour at 12 volts. Charging with 2 Prosine 2.0 inverter/chargers for a total of 200 Amps. charge current. But be careful, even with AGM batteries it's important to never allow them to be completely discharged. This will shorten their useful life. 50% discharge is the rule of thumb maximum.

Calculate the load averages for all devices that will be running through the night and try to not exceed 1/2 of the total Amp./Hour rating of your battery bank. If memory serves, the furnace fan pulls around 10 Amps. when running, and the inverter can easily pull 10 to 20 Amps. just powering all the little chargers and things in the coach. I used to have a chart that I made up with typical load values that I can try to dig up if anyone is in need of those numbers.

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Have Fun!! Mark & Donalda 04 Horizon 40WD no TOW 90,900+ miles and counting
Triumph Bonneville & Susuki S40 on the back

Ok, I just went to Sears and bought a Hydrometer (sp?) and went over to test each of my batteries. As you all expected, each one of the three batteries had one to two dead cells. I yanked them all and will replace them this week.

Buster661, Sorry to hear about your batteries. What kind were they and what size were they? I'm just curious because mine are 4 Years old and I'm wondering when they will expire. Thanks, Indiana Journey

They were Interstate RV/Marine. They were stamped 8/06. I just bought the coach so I do not know how well the previous own maintained them. On my last coach my batteries lasted about 3.5 to 4 years before they would not hold a charge any longer.

Before you spend the money on AGM batteries you might check to see if you have a Parrallux converter. They will just cook you batteries. You may be better off changing the converter to a Progressive Dynamics (Charge Wizard converter) and just use standard deep cycle batteries from Wal-Mart. That's what I did and everything works just fine.

For the good ones (Lifeline AGMs) you'll pay at least $300.00+ apiece. Either 2ea. or 4ea. 6 volt or 2ea. or 3ea. 12 volt depending on what you can squeeze into the space. A reasonably good RV/Marine Deep cycle battery will probably cost less than $100.00 ea. and should last 3 to 4 years if you manage the discharge cycle depth of discharge. Same applies to the AGMs but they are more tolerant of deeper discharges and will allow for many more discharge cycles.

Since the AGMs have all of the electrolyte held in suspension by the glass mats, they usually give you more Amp./Hours per pound than flooded lead acid's do.

I agree with Bayway on the converter/charger. You should monitor the charge voltage very carefully with a good digital voltmeter for a while both before and after installing new batteries to see if an overcharge condition is boiling away all the acid. At 70 degrees Fahrenheit, the charger output under float conditions should not exceed 13.4 volts. 13.0 to 13.4 is good. Below 13.0 is a bit too low for flooded or AGM.

I think your coach may have come with a Xantrex Trace 2 kVA modified sine wave inverter/charger. But the float charge values remain the same regardless of brand of inverter/charger or converter/charger.

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Have Fun!! Mark & Donalda 04 Horizon 40WD no TOW 90,900+ miles and counting
Triumph Bonneville & Susuki S40 on the back